Miniature camera with front wall cover

ABSTRACT

A miniature camera having a generally rectangular front wall provided with elongated top and bottom edges and opposed end edges which are substantially shorter than the top and bottom edges. At least one cover plate is pivotally connected to the housing of the camera for swinging movement about an axis parallel to the top and bottom edges of the front wall between a closed position covering at least part of the front wall and an open position uncovering the latter part of the front wall. This part of the front wall is provided with openings through which light can reach an objective and a viewfinder, so that when the cover plate is in its closed position these openings are covered to protect the objective and viewfinder against dust, foreign matter, and the like.

- United States Patent Lange Sept. 17, 1974 [5 MINIATURE CAMERA WITH FRONT WALL 3,602,118 8/1971 Oberheim 95111 R COVER FOREIGN PATENTS OR APPLICATIONS Inventor: Karl-Heinz g Bunde, Germany 1,105,407 3/1968 7 Great Britain 95111 R Assigneez Balda werke photographische I 681,557 3/1964 Canada 95/11 R Gerate Und Kunststoif GmbH & Co.

Przmary Exammer-Robert P. Greiner KG, Bunde, Germany Attorney, Agent, or F1rmBlum Moscovitz FrIedman [22] Filed: May 29, 1973 & K l

[21] Appl. No.: 364,856

[57] ABSTRACT 30 F A u M D ta A miniature camera having a generally rectangular 1 J g f r g ca y a 2226808 front wall provided with elongated top and bottom une many edges and opposed end edges which are substantially shorter than the top and bottom edges. At least one [52] US. Cl 354/287, 354/266, 354/288, cover plate is pivotally connected to the housing of 1 350/60 7 the camera for swinging movement about an axis parallel to the top and bottom edges of the front wall be- 350/59 6 tween a closed position covering at least part of the front wall and an open position uncovering the latter part of the front wall. This part of the front wall is pro- [56] References cued vided with openings through which light can reach an UNITED STATES PATENTS objective and a viewfinder, so that when the cover 1,814,973 7/ 1931 Silva 95/ll R plate is in its closed position these openings are cov- $RkiImerered to protect the objective and viewfinder against ose 3,399,011 8/1968 Heiniger.... 95/11 R x dust forelgn matter and the l 6 3,491,665 1/1970 Fischer 95/11 R 10 Claims, 7 Drawing Figures I I I, 13 Q 11 U BQLDQ .u-um- L 3 PATEMEUSEH 3.836.9855

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PAIENIEDSEPITIIQH. 3.836.985-

' sum 2 or 4" 11 MINIATURE CAMERAWITH FRONT W LL cov R BACKGROUND OF THE INVENTION The present invention relates to cameras.

The present invention relates in particular to miniature cameras of the type having an elongated, relatively narrow, horizontally extending front wall formed with openings through which light can reach such components as the objective and the viewfinder of the camera.

Known cameras of this type have freely exposed viewfinders and an objective which is protected by a shiftable relatively rigid cover slide. In order to make an exposure it is necessary to shift this cover slide laterally away from the objective alongthe front of the camera housing to a location situated beside the objective. Such a rigid shiftable slide member cannot, however, cover all of the components, such as a viewfinder, light meter, and objective, which are distributed along the narrow front wall of the camera, since there is insufficient space at the front wall of a camera of this type to permit such a shiftable member to move laterally through a distance sufficient to uncover all of the elements essential to making an exposure. Therefore, with the known cameras of this .type the objective is covered but the viewfinderremainsjat alltimes uncovered. This construction is highly unsatisfactory for miniature cameras which are commonly placed in the pocket of a garment without a camera case. There is of course the possibility of utilizing, instead of a rigid shiftable cover slide, a flexible slide which is capable of uncovering the front components of the camera by being shifted around a front edge of the camera parallel to a side wall thereof. Such a covering arrangement, however, is of little stability and is easily subject to faulty operation. The operation of such construction is very seriously impaired by becoming clogged with foreign particles which cannot be avoided when the camera is stored in the pocket of an article of clothing such as a pair of trousers or a jacket.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to avoid the above drawbacks.

Thus, it is an object of the present invention to provide for a camera of the above general type a strong, reliable covering structure composed of a relatively small number of elements and having a closed position capable of covering both a viewfinder and an objective as well as an open position uncovering these components.

A further object of the present invention is to provide a covering structure of the above general type which will serve the added function of a sun shade, in a manner similar .to a visor.

Yet another object of the present invention is to provide a structure of the above general type which can be readily displaced between open and closed positions by manipulation of a shiftable component with the covering structure of the invention being capable of remaining reliably in a given end position until displaced therefrom by the operator.

A further object of the present invention is to provide a construction of the above general type which is capa- '2 ble of preventing tripping of the shutter to make an exposure when the front wallis covered.

It is especially an object of the present invention to provide a construction of the above general type in which the cover will reliably remain in its open position uncovering such components as the'objective and viewfinder, so that undesired covering of these components against the will of the operator cannot take place.

Yet a further object of the presentinvention is to provide a construction of the above general type which enables the camera to be readily carried about in the pocket of an article of clothing, even if the camera is not in a camera case, without any possibility of undesirablejamming of the movable components which serve to cover and uncover the front wall of the camera.

Also, the object of the present invention include a structure of the above general type which does not have the effect of undesirably increasing the dimensions of the camera when the cover is in its open position.

According to the invention the camera has a housing provided with a generally rectangular front wall having top and bottom parallel edges which are substantially longer than opposed end edges of the camera front wall. At the front wall of the camera there are openings through which light has access to an objective and a viewfinder of the camera. A cover plate is pivotally connected to the camera for swinging movement about an axis parallel to the top and bottom edges of the front wall between a closed position covering these front wall openings and an open position uncovering these openmgs.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a perspective illustration of a camera of the invention showing the cover structure in its open position;

FIG. 2 is a perspective illustration showing the cover structure of FIG. 1 in its closed position;

FIG. 3 is a fragmentary partly sectional perspective illustration showing details ofa mechanism for bringing about closing and opening of the front wall covers;

FIG. 4 is a schematic illustration of the manner in which a pair of covers are connected to each other as well as showing a further embodiment of a transmission for swinging of the coversbetween their closed and open position;

FIG. 5 is a schematic partly sectional fragmentary illustration of a further embodiment according to which there is only one cover plate;

FIG. 6 is a fragmentary side elevation of the camera showing one type of construction for releasably holding the covers in their open-and closed position; and

FIG. '7 is a fragmentary partly sectional side elevation showing another embodiment of a structure for releasably holding the covers in their closed and open positions.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 2, it will be seen that the camera of the invention has a housing 1 and is in the form of a miniature camera adapted to be handheld and having a substantially rectangular relatively flat or shallow configuration. Thus the camera shown in FIGS. 1 and 2 is small enough to fit comfortably into the pocket of a garment. The camera housing 1 has a front wall 2 which is of a generally rectangular configuration, this front wall 2 having top and bottom edges and opposed end edges which are considerably shorter than the top and bottom edges, as is readily apparent from FIGS. 1 and 2. In the example of FIGS. 1 and 2, a pair of cover plates 3 and 4 are pivotally connected to the housing I for respective swinging movement about axes which are respectively parallel to the bottom and top edges of the front wall 2. These swingable cover plates 3 and 4 are capable of being turned from a closed position which is shown in FIG. 2, where they cover front wall openings 5-8 which respectively are capable of permitting light to have access to an objective, a range finder, a light meter, and a viewfinder. Thus, when the cover plates 3 and 4 are in the closed position shown in FIG. 2, the openings 5-8 through which light has access tov the above components are covered so that the components themselves or windows at these openings are protected against becoming fowled by dust or other foreign matter.

These cover plates 3 and 4 are capable of being swung from the closed position of FIG. 2 into the open position of FIG. 1. Thus it will be seen that the cover plates 3 and 4 are in the nature of visors, and the upper cover plate 4 in particular is capable of acting as a sun shade when this upper cover plate 4 is in the open position shown in FIG. 1. In addition, the inner surfaces of the cover plates 3 and 4 are formed with a longitudinal fluting 9 forming a series of relatively small ribs and grooves which reduce undesirable effects of light reflection.

In the illustrated example the ends of the cover plates 3 and 4 are respectively provided with walls 10 and II which are normal to the turning axes of the cover plates and which form gear sectors meshing with each other, as described below, so that these gear sectors 10 and 11 at the corresponding ends of the cover plates 3 and 4 compel the latter to swing equally and oppositely to each other. It will be noted from FIG. I that the inner surfaces of the gear sectors 10 and II are also provided with the fluting for reducing light reflection.

At the upper wall of the housing I there is, accessible to the operator, a shutter-tripping button 12 capable of being depressed by the operator in order to trip the shutter and make an exposure. Furthermore, at the left end of the housing 1, as viewed in FIGS. I and 2, there is a manually operable means 13 in the form of a plate capable of being slidably moved longitudinally of the left end wall ofthe housing 1 forwardly and rearwardly for the purpose of displacing the cover plates 3 and 4 between their open and closed positions shown in FIGS. I and 2, in a manner described in greater detail below.

Referring to FIG. 4, it will be seen that the cover plates 3 and 4 are pivotally connected to the housing I for respective swinging movement about the axes of a pair of pivot pins 15 and 16 which are respectively fixed to the end walls 10 and 11 and which are received in suitable bearings in the housing. These pivot pins 15 and 16 fixed to and projecting from the pair of gear portions 10 and 11 at the left end of the plates 3 and 4 are apparent in FIG. 3. FIG. 4, however, clearly shows how the gear sector 10, at each end of the lower cover plate 3, has teeth 14 which mesh with teeth 14a of the gear sector 11 at each end of the upper cover plate 4. This coaction between the cover plates through the meshing gear sectorsis not so clearly apparent from FIGS. 1-3. With this construction either in response to manipulation of the manually operable means 13 or in response to direct-manipulation of one or the other of the cover plates 3 and 4 by the operator, if desired, it is possible to swing the cover plates 3 and 4'between their open and closed positions respectively illustrated in FIGS. 1 and 2.

In the particular embodiment which is shown in FIG. 4, there is fragmentarily illustrated an extension 210 of the manually shiftable slide plate 13. This extension 21a which is fixed to the slide plate 13 for longitudinal shifting movement therewith along the left end of the camera, as viewed in FIGS. 1 and 2, has at its lower edge, at the region of its right free end, as viewed in FIG. 4, a series of teeth so that the extension 21a forms a rack. A further gear sector 21b is fixed to the sector 10 concentrically therewith in the manner shown in FIG. 4, and the teeth of the smaller sector 21b mesh with the teeth of the rack 21a, so that with this construction as the plate 13 is shifted forwardly the cover plates 3 and 4 will be swung open, while when the plate 13 is shifted rearwardly the cover plates will be closed.

FIG. 3 illustrates another embodiment of a transmission between the manually operable means 13 and the gear sectors 10 and 11 at the left end of the cover plates 3 and 4. Thus, as may be seen from FIG. 3, the shiftable slide plate 13 which can be manually displaced by the operator is fixed with a pair of extensions 21 and 22 which respectively terminate in pins 19 and 20 which extend parallel to the pivot pins 15 and 16, respectively. The gear sectors 10 and 11 are respectively formed with curved slots 17 and 18 which respectively receive the pins 19 and 20, so that in this way the extensions 21 and 22 of the slide plate 13 have pin-and-slot connections with the sectors 10 and 11. As a result when the plate 13 is shifted forwardly in the direction of the arrow 24, the gear sectors 10 and I1 and the cover plates 3 and 4 therewith will be swung in the opening direction to displace the cover plates 3 and 4 from the closed to the open position, while when the plate 13 is returned to its rear end position the plates 3 and 4 will be returned to their closed position shown in FIG. 2.

It will be noted from FIG. 3 that in addition to the extensions 21 and 22, the manually operable slide plate 13 has an extension 23 which becomes situated beneath the shutter-tripping button 12 when the plate 13 is in its rear, retracted position, corresponding to the closed position of the cover plates 3 and 4. As a result when the cover plates 3 and 4 are in their closed position, the extension 23 is in a blocking position preventing downward movement of the button 12 so that the operator cannot trip the shutter at this time. However, when the plate 13 is shifted forwardly to open the cover plates 3 and 4, the blocking extension 23 becomes situated forwardly beyond the button 12 so that now the plate 23 is in a released position releasing the shutter button 12 for depression by the operator, and thus at this time it is possible to make an exposure.

According to the embodiment of the invention which is shown in FIG. 5, there is a single cover plate 27 instead of a pair of cover plates 3 and 4. This single cover plate 27 is of course wider than either of the cover plates 3 and 4 so that when the cover plate 27 is in the closed position shown in solid lines in FIG. 5, it will extend through the distance between the top and bottom edges of the front wall 2. This plate 27 is pivotally supported by pivots 16 as shown schematically in-FIG. 5, in the same way as the upper cover plate 4. The single cover plate 27 can be manually swung between the closed position shown in solid lines and the open position shown in dot-dash lines in FIG. 5, or any suitable transmission may be provided such as that of FIG. 4 or that of FIG. 3, enabling the plate 27 to be swung between its open and closed positions from a manually operable mean such as the shiftable plate 13.

FIG. 5 shows one embodiment of a means for maintaining a cover plate in at least one of its end positions. This means in FIG. .5 takes the form of the illustrated over-center spring 25. This over-center spring 25 has an intermediate coiled portion and a pair of springy arms projecting therefrom in the manner shown in FIG. 5. The lower springy arm is supported for swinging movement about a fixed axis, while the upper springy arm of the spring 25 is pivotally connected with the plate 27 in a manner shown in FIG. 5. Thus, in the illustrated position of the spring 25 it will urge the plate 27 in a clockwise direction about the pivot 16 to maintain the cover plate 27 in its closed position. However, when the cover plate 27 is swung to the open position shown in dot-dash lines in FIG. 5, the upper end of the spring 25 will become situated closest to the lower end thereof when this upper end is in a plane which contains the axis of the pivot pin 16 and the axis of the pin to which the lower end of the spring 25 is connected. When the upper end of the spring 25 is in this latter plane the spring is at its dead center position. As soon as the upper end of the spring 25 moves beyond this dead center position in a counterclockwise direction, as viewed in FIG. 5, around the axis ofthe pivot pin 16, the spring 25 will again tend to expand and will resiliently urge the plate 27 to the dot-dash line position, so that the single over-center spring 25 of FIG. 5 will maintain the plate 27 both in its open position and in its closed position.

As is apparent from FIGS. 6 and 7, the means for retaining the cover plates eitherin their open position or in their closed position can be directly connected with the manually operable means 13. Thus, FIG. 6 shows an over-center spring 30 connected at one end 32 to the slide plate 13 for movement therewith, while the other end 33 is supported on a stationary pivot. Thus, as the plate I3 is shifted forwardly in the direction of the arrow 24 shown in FIG. 6, the top end of the spring 30 will approach a vertical plane which contains the axis of the pivot on which the end 33 of the spring 30 is mounted. When the two ends of the spring 30 are in this vertical plane, the spring 30 is in its dead center position. As soon as the top end of the spring 30 moves to the right beyond the vertical plane containing the pivot axis of the end 33 of the spring 30, the spring 30 will tend to expand to urge the plate 13 in the direction of the arrow 24, and thus the spring 30 will serve to maintain the cover plates 3 and 4 in their open position. During retraction of the slide 13, as soon as the top end of the spring 30 moves to the left of the lower end thereof. the spring 30 will act to urge the plate 13 to the left, as viewed in FIG. 6, thus maintaining the plate 13 in its rear position corresponding to the closed position of the plates 3 and 4.

According to the embodiment of the invention shown in FIG. 7, the lower edge 36 of the plate 13 is formed with a pair of downwardly directed V-notches 38 and 40. The housing 1 carries at its bottom wall a springpressed ball 42 which forms a detent structure with the V-notches 38 and 40. Thus, when the plate 13 is in its retracted rear position, corresponding to the closed position of the cover plates 3 and 4, the ball 42 is received in the front notch 40, while when the plate 13 is shifted forwardly the ball 42 will be received in the notch 38 when the plate 13 has reached a position corresponding to the open position of the'cover plates 3 and 4. Thus the detent structure of FIG. 7 will also serve to retain the cover plates 3 and 4 either in their open or closed position.

While an arrangement as shown in FIG. 5, where there is a single cover plate 27, is capable of achieving the desired results, this arrangement has a certain disadvantage with respect to the fact that the single cover plate 27 will project forwardly beyond the top wall of the camera through a substantial distance when the cover plate 27 is in the open position shown in dot-dash lines in FIG. 5. By providing a pair of plates 3 and 4, however, the extent to which the plates 3 and 4 increase the dimensions of the top and bottom walls of the camera is substantially reduced, being no more than half the extent of increase provided by a single plate 27, so that the use of a pair of plates 3 and 4 is preferred for those situations where it is undesired to increase substantially the forward extension of the cover plates beyond the front wall 2 of the camera.

A further feature of the invention resides in the fact that the cover plates 3 and 4 engage each other along a line of contact 26 indicated in FIG. 3. This line of contact 26 where the edges of the plates 3 and 4 engage each other serves to provide the required closure of the front wall openings and the required protection of the camera. In accordance with the invention the line of contact 26 of the free edges of the cover plates 3 and 4 is situated forwardly of a plane which contains the axes of the pivots l5 and 16. As a result the extent to which the plates 3 and 4 must be swung between their closed and open positions is reduced. Thus, the relatively small extent of longitudinal movement of the slide 13 along an end of the housing 1 is apparent from the distance between the V-notches 38 and 40 of FIG. 7. With this small extent of movement it is possible to swing the plates 3 and 4 between their open and closed positions at least in part because of the location of the line of contact 26 forwardly of the plane which contains the axes of the pivots l5 and 16.

With the embodiments of the invention described above, each cover plate can take the form of a relatively rigid stable component manufactured by injection molding, for example, so that the reliable functioning of the cover plate structure of the invention is assured. As was indicated above, the cover plate which swings upwardly to its open position also functions at the same time as a sun shade.

It is furthermore to be noted that where the cameras has a pair of cover plates 3 and 4 which are swingable equally and oppositely, if these plates are actuated from a manually operable means such as the shiftable slide 13, then the actuation of such a pair of cover plates is easier to bring about because of the smaller paths of swinging movement of such a pair of cover plates, as contrasted with a single cover plate as shown .in FIG. 5. Thus the use of a pair of cover plates 3 and 4 is also of advantage when a manually operable means is available for actuating the cover plates.

While the means 13 is shown in FIG. 3 as actuating both of the cover plates, where they are connected to gear sectors which mesh with each other, as shown in FIG. 4, it is possible to provide a transmission from a means 13 only to one of the cover plates, and the transmission to the other will be assured through the meshing gear sectors.

The provision of the gear sectors at both ends of the cover plates is of advantage with respect to the stability and rigidity of the structure since in this way the cover plates will resist twisting with each cover plate reinforcing the twisting resistance of the other cover plate due to the meshing of the gear sectors at the ends of the cover plates.

Moreover, the use of means for retaining the cover plates in their end positions, such as the over-center springs referred to above or the detent structure of FIG. 7 reliably prevents closing of the cover plates when it is intended to maintain them open during use of the camera. A further advantage of the invention resides in the fact that the means 13 is very convenient to operate, requiring only a simple longitudinal shifting movement forwardly or rearwardly to bring about the desired swinging movement of at least one of the cover plates.

Of course, the use of the blocking projection 23 prevents inadvertent tripping ofthe shutter when the cover plates are in their closed positions.

What is claimed is:

1. ln a miniature camera, a housing of relatively thin, flat configuration having a front wall of at least substantially rectangular, narrow, strip-shaped configuration provided with opposed relatively long top and bottom edges and opposed relatively short end edges extending between said top and bottom edges and having a length substantially less than one-half the length of said top and bottom edges, said housing havingtop and bottom walls extending rearwardly from said top and bottom edges and spaced from each other by the same distance as said top and bottom edges and opposed end walls extending rearwardly from said end edges and spaced from each other by the same distance as said end edges, the said front wall being formed with openings through which light has access to an objective and viewfinder situated in said housing behind said openings, and the latter openings being distributed longitudinally of said front wall with each opening situated between the other opening and one of said end edges, and at least one cover plate situated at all times between a pair of planes which contain said end walls, said cover plate being pivotally connected to said housing for swinging movement about an axis substantially parallel to and situated closely adjacent and extending along said top edge of said front wall between a closed position in front of said front wall covering said front wall openings and an open position uncovering said openings to an extent sufficient to permit light to reach said opening from a location situated forwardly of said front wall, a pair of said cover plates are pivotally connected to said housing for swinging movement about a pair of axes, respectively, which are substantially parallel to and located closely adjacent and extending along said top and bottom edges of said front wall in a manner similar to swingable visors between a closed position covering said openings of said front wall and an open position uncovering said openings, said cover plates having elongated free edges distant from and substantially parallel to said axes, and said free edges engaging each other in the closed position of said cover plates so that the latter do not overlap each other in the closed position thereof.

2. The combination of claim 1, and wherein said cover plates are respectively fixed with gear sectors normal to said axes and meshing with each other for constraining said cover plates to move equally and oppositely between said closed and open positions.

3. The combination of claim 2 and wherein said gear sectors are situated at each end of said cover plates.

4. The combination of claim 2 and wherein a means coacts with at least one of said cover plates for releasably retaining the latter in its open position.

5. The combination of claim 2 and wherein a manually operable means is carried by said housing for slidable movement with respect thereto and is operatively connected with said cover plate for turning the latter between its open and closed positions.

6. The combination of claim 5 and wherein said manually operable means has a pin-and-slot connection with said cover plate.

7. The combination of claim 5 and wherein said manually operable means has an elongated rack portion and said cover plate is fixed with a toothed sector meshing with said rack portion to be rotated in response to movement of said manually operable means.

8. The combination of claim 5 and wherein said manually operable means has a pair of end positions corresponding to the closed and open positions of said cover plate, and means coacting with said manually operable means for releasably retaining the latter in at least one of its end positions.

9. The combination of claim 5 and wherein a shutterrelease member is carried by said housing, said manually operable means having a blocking position blocking operation of said shutter-release member when said cover plate is in its closed position and an unblocking position releasing said shutter-release member for operation when said manually operable means has displaced said cover plate to its open position.

10. The combination of claim 1 and wherein said cover plates when in said closed position engaging each other along a contact line which is situated forwardly of a plane which contains the pair of axes about which said cover plates are swingable. 

1. In a miniature camera, a housing of relatively thin, flat configuration having a front wall of at least substantially rectangular, narrow, strip-shaped configuration provided with opposed relatively long top and bottom edges and opposed relatively short end edges extending between said top and bottom edges and having a length substantially less than one-half the leNgth of said top and bottom edges, said housing having top and bottom walls extending rearwardly from said top and bottom edges and spaced from each other by the same distance as said top and bottom edges and opposed end walls extending rearwardly from said end edges and spaced from each other by the same distance as said end edges, the said front wall being formed with openings through which light has access to an objective and viewfinder situated in said housing behind said openings, and the latter openings being distributed longitudinally of said front wall with each opening situated between the other opening and one of said end edges, and at least one cover plate situated at all times between a pair of planes which contain said end walls, said cover plate being pivotally connected to said housing for swinging movement about an axis substantially parallel to and situated closely adjacent and extending along said top edge of said front wall between a closed position in front of said front wall covering said front wall openings and an open position uncovering said openings to an extent sufficient to permit light to reach said opening from a location situated forwardly of said front wall, a pair of said cover plates are pivotally connected to said housing for swinging movement about a pair of axes, respectively, which are substantially parallel to and located closely adjacent and extending along said top and bottom edges of said front wall in a manner similar to swingable visors between a closed position covering said openings of said front wall and an open position uncovering said openings, said cover plates having elongated free edges distant from and substantially parallel to said axes, and said free edges engaging each other in the closed position of said cover plates so that the latter do not overlap each other in the closed position thereof.
 2. The combination of claim 1, and wherein said cover plates are respectively fixed with gear sectors normal to said axes and meshing with each other for constraining said cover plates to move equally and oppositely between said closed and open positions.
 3. The combination of claim 2 and wherein said gear sectors are situated at each end of said cover plates.
 4. The combination of claim 2 and wherein a means coacts with at least one of said cover plates for releasably retaining the latter in its open position.
 5. The combination of claim 2 and wherein a manually operable means is carried by said housing for slidable movement with respect thereto and is operatively connected with said cover plate for turning the latter between its open and closed positions.
 6. The combination of claim 5 and wherein said manually operable means has a pin-and-slot connection with said cover plate.
 7. The combination of claim 5 and wherein said manually operable means has an elongated rack portion and said cover plate is fixed with a toothed sector meshing with said rack portion to be rotated in response to movement of said manually operable means.
 8. The combination of claim 5 and wherein said manually operable means has a pair of end positions corresponding to the closed and open positions of said cover plate, and means coacting with said manually operable means for releasably retaining the latter in at least one of its end positions.
 9. The combination of claim 5 and wherein a shutter-release member is carried by said housing, said manually operable means having a blocking position blocking operation of said shutter-release member when said cover plate is in its closed position and an unblocking position releasing said shutter-release member for operation when said manually operable means has displaced said cover plate to its open position.
 10. The combination of claim 1 and wherein said cover plates when in said closed position engaging each other along a contact line which is situated forwardly of a plane which contains the pair of axes about which said cover plates are swingable. 